A major reason to why harold lost was due to his army was exhausted and weakened in numbers. The battle of stanford bridge was a gruesome one with the norsemen refusing to surrender untill the next day were Hardras son Olav agreed to give himself up and never return to england. The arm then rested, some sources claim that harold had an argument with his army claiming that ahrold had not shared the trophies of battle out fairly,prehaps he had insisted on keeping the viking fleet which would have been a tremendous national asset. A weekafter the battle the norsemen were gone and celebratiosn began meanwhile news was travelling that william had landed on Pevensey.
Harold immediately assembled the housecarls who had survived and marched south. He travelled at such a pace that many of his troops failed to keep up with him (weakening his army). The Anglo saxon army travlled 250 miles to hastings from the 5th to the 13th of october .Wjen arriving in london Harold's brother, , offered to lead the army against William, stating that as king he should not risk the chance of being killed. Harold rejected the advice and after five days Harold decided to head for the south coast without his northern troops. This was a big mistake of Harold as he should have taken his brothers advice instead of being killed in the battlefield and by not doing so has lost osme northern troops. The army must have been weary encouraged by the strong vicotry at stanfod bridge and gain in arms however the army was cut they were also more drained.
Another important reason to why william down in size and a lot weaker than they previously were. In my opion this is the main reason to why Harold lost. His men was majorly cut down in size and being that his army was prodmitatly made up of fryds so there loyalty was doubting.Also they were celebrating there success of winning the battle by getting merry. So aswell as bein exhausted won the battle was due to his tactics and skillfull fighters. It is estimated that that William had 5,000 infantry and 3,000 while Harold had about 2, 500 and over 6,000 members of the . So prodimataley harolds army were inexperienced fighters whereas willaims were a trained army.The norman army fought on caverlry and had highly skilled archers, whereas the anglo saxon army was made from mainly local men (fyrds) and bretons which were a loyal professional army. Harodls army was not as strong as williams thus why eh lsot the battle. The leaders of the fyrd, (the thegns) were strong and had and but the rest of the men were inexperienced fighters and many were simple thugs there unadvanced weapons such as iron-studded clubs, scythes, slings, reaping-hooks and hay-forks were no where near as advanced as willaims calvery and accuriate archers.
Also Harolds army failed to keep up with modern armies like that of . While William's knights walked to the battle leading their horses, in order to keep their mounts fresh, the Huscarls did the opposite, riding to the battle, and later dismounting to fight on foot giving them a major disadvantage on the battle field.
the English shield wall grew smaller and smaller, many of the fyrdmen in the back ranks clustered closer together behind the thinning wall of housecarls weaking the defence.
The idea that William was a better leader is a mild reason to why William won the battle. Before 1066 William had already demonstrated his strength as a commander and soldier. His life was one of almost constant warfare as he carved out for himself a position as one of the most powerful and, when necessary, ruthless rulers of his day. He had experienence in leadership for example In 1053 he suppressed a revolt led by William of Arques. Whereas some sources claim (however reliability is not certain) that at stamford bridge Harold fell out with his army over a disagreement over distribution over gains. This shows Harold lack of communication with his forces which is a contrast against the strong communication and organisation of willaims.
However in my opion the least imortant reaosn to why william won yet still important is the fact that william supposidly had god on his side. William also had better leadership skills than harold. Religion was extremely important in the 1066 in both norman and anglo saxon culture. William could not just demand support from his nobles, he had to convince them of his case. He needed to show his followers that his claim was a lawful one, and that he had God on his side. So when he decided on invasion, he took elaborate measures to ensure he had strong support, and even sent an envoy to the Pope asking for his blessing, the pope supported willaims claim , this was a major advantage to willaim as the fighters would have belived that they could win the battle if god was on there side. Also they would have been more likely to fight harder and risk there lives if it meant fighting for god it meant a door open to heaven. During the battle flags with crosses and religious symbols were held. This made the battle look more like a crusade rather than a war. The thought of dying for god grew loyalty with Williams men which reflected in the outcome of the battle.
Overall there are many reaons to why William won the battle of Hastings. The Luk and timing is in my opinion the most important reason as without this William would have arrived at Hastings with a saon waiting army and darnet of stood a chance. So without Stamford bridge and the change of weather in that week I would have been surprised if Williams men would have made it past pevansey.